<html>
<!--
https://bugzilla.mozilla.org/show_bug.cgi?id=1268195
-->
<head>
  <meta charset="utf-8">
  <title>Test for Bug 1268195</title>
  <script type="application/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
  <style>
    html, body {
        margin: 0;
        padding: 0;
    }

    .noscroll {
        overflow: hidden;
        height: 100%;
    }

    /* Toggling this on and off triggers a frame reconstruction on the <body> */
    html.reconstruct-body::before {
        top: 0;
        content: '';
        display: block;
        height: 2px;
        position: absolute;
        width: 100%;
        z-index: 99;
    }
  </style>
  <script type="application/javascript">
    SimpleTest.waitForExplicitFinish();

    function run() {
        // Make sure we have the right scroll element
        SimpleTest.is(document.body.scrollTopMax > 0, true, "Body is the scrolling element");

        // Scroll to the bottom
        document.body.scrollTop = document.body.scrollTopMax;
        SimpleTest.is(document.body.scrollTop > 0, true, "Scrolled body");

        // Do a frame reconstruction on the body while also shortening the
        // height.
        document.body.classList.toggle('noscroll');
        document.documentElement.classList.toggle('reconstruct-body');
        document.getElementById('spacer').style.height = '1px';
        SimpleTest.is(document.body.scrollTop, 0, "Scroll forced to top");

        // Do another frame reconstruction while lengthening the height again.
        document.body.classList.toggle('noscroll');
        document.documentElement.classList.toggle('reconstruct-body');
        document.getElementById('spacer').style.height = '5000px';
        SimpleTest.is(document.body.scrollTop, 0, "Scroll remained at top");

        SimpleTest.finish();
    }
  </script>
</head>
<body onload="setTimeout(run, 0)">
<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1268195">Mozilla Bug 1268195</a><br/>
The scroll position should end the top of the page. This is the top, yay!
<div id="spacer" style="height: 5000px"></div>
The scroll position should end the top of the page. This is the bottom!
<pre id="test">
</pre>
</body>
</html>
